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Abstract:

A touch input method and a device thereof are disclosed. The touch input
device includes a display module for displaying an image, a backlight
module for emitting a light source, at least one light-sensing unit for
sensing a reflected light of the light source reflected by at least one
object on the display module and generating a light intensity signal
correspondingly, and a processing module for receiving the light
intensity signal and determining based on the light intensity signal at
least one touch point on the display module touched by the object. The
touch input method is applicable to the touch input device and includes
the steps of using the processing module to receive the image, using the
processing module to analyze the image and obtain an image analysis
result, and regulating a light intensity of an invisible light emitted
from the backlight module based on the image analysis result.

Claims:

1. A touch input method applicable to a touch display, the touch display
comprising a display module, a backlight module, at least one
light-sensing unit and a processing module, the display module being
adapted to display an image, the backlight module being adapted to emit a
light source, the at least one light-sensing unit being adapted to sense
a reflected light of the light source reflected by at least one object on
the display module and generate a light intensity signal correspondingly,
and the processing module being adapted to receive the light intensity
signal and determine based on the received light intensity signal at
least one touch point on the display module touched by the at least one
object, the touch input method comprising the following steps of: using
the processing module to receive the image displayed on the display
module; using the processing module to analyze the image to obtain an
image analysis result; and using the processing module to regulate a
light intensity of an invisible light emitted from the backlight module
according to the image analysis result.

2. The touch input method as claimed in claim 1, wherein the image
analysis result is a gray level distribution analysis result.

3. The touch input method as claimed in claim 1, wherein the backlight
module further includes at least one red light emitting unit, one green
light emitting unit, and one blue light emitting unit; and the invisible
light is additionally emitted from the red light emitting unit.

4. The touch input method as claimed in claim 1, wherein the image
analysis result is a red light distribution analysis result.

5. A touch input device, comprising: a display module capable of
displaying an image; a backlight module capable of emitting a light
source; at least one light-sensing unit capable of sensing a reflected
light of the light source reflected by at least one object on the display
module and generating a light intensity signal correspondingly; and a
processing module being connected to the display module, the backlight
module and the at least one light-sensing unit; and the processing
module, the processing module capable of receiving the light intensity
signal and determining based on the received light intensity signal at
least one touch point on the display module touched by the at least one
object; wherein the processing module receives the image displayed on the
display module and analyzes the image to obtain an image analysis result,
and regulates a light intensity of an invisible light emitted from the
backlight module according to the image analysis result.

6. The touch input device as claimed in claim 5, wherein the invisible
light is an infrared (IR) light.

7. The touch input device as claimed in claim 6, wherein the backlight
module further includes at least one infrared (IR) light emitting unit
for emitting the IR light.

8. The touch input device as claimed in claim 7, wherein the backlight
module further includes at least one red light emitting unit, one green
light emitting unit and one blue light emitting unit; and the IR light
additionally is emitted from the red light emitting unit.

9. The touch input device as claimed in claim 5, wherein the at least one
light-sensing unit is arranged inside the backlight module.

10. A touch input method applicable to a touch display, the touch display
including a display module, a backlight module, at least one
light-sensing unit, a storage unit and a processing module, the display
module being adapted to display an image, the backlight module being
adapted to emit a light source, the at least one light-sensing unit being
adapted to sense a reflected light of the light source reflected by at
least one object on the display module and generate a light intensity
signal correspondingly, the storage unit being adapted to store a
threshold value, and the processing module being adapted to receive the
light intensity signal and the threshold value and compare the light
intensity signal with the threshold value in order to determine at least
one touch point on the display module touched by the at least one object,
the touch input method comprising the following steps of: using the
processing module to receive the image displayed on the display module;
using the processing module to analyze the image to obtain an image
analysis result; and using the processing module to adjust the threshold
value according to the image analysis result.

11. The touch input method as claimed in claim 10, wherein the image
analysis result is a gray level distribution analysis result.

12. The touch input method as claimed in claim 10, wherein the image
analysis result is a red light distribution analysis result.

13. A touch input device, comprising: a display module capable of
displaying an image; a backlight module capable of emitting a light
source including an invisible light; at least one light-sensing unit
capable of sensing a reflected light of the light source reflected by at
least one object on the display module and generating a light intensity
signal correspondingly; a storage unit capable of storing a threshold
value; and a processing module being connected to the display module, the
backlight module, the at least one light-sensing unit and the storage
unit; the processing module capable of receiving the light intensity
signal and the threshold value, and comparing the light intensity signal
with the threshold value in order to determine at least one touch point
on the display module touched by the at least one object; wherein the
processing module receives the image displayed on the display module and
analyzes the image to obtain an image analysis result, and adjusts the
threshold value according to the image analysis result.

14. The touch input device as claimed in claim 13, wherein the invisible
light is an IR light.

15. The touch input device as claimed in claim 14, wherein the backlight
module further includes at least one IR light emitting unit for emitting
the IR light.

16. The touch input device as claimed in claim 15, wherein the backlight
module further includes at least one red light emitting unit, one green
light emitting unit and one blue light emitting unit, and the IR light is
additionally emitted from the red light emitting unit.

Description:

FIELD OF THE INVENTION

[0001] The present invention relates to a touch input method and a device
thereof, and more particularly to a touch input method and a device
thereof in which a displayed image content is used as a reference for
determining touch information.

BACKGROUND OF THE INVENTION

[0002] Generally, in a liquid crystal display (LCD), a backlight module is
used to produce a light source, and the transmittance of the backlight is
changed by controlling the twist and deformation of the liquid crystal,
in order to determine the brightness of the image displayed on the
display. Currently, the LCD displays the image mainly using cold cathode
fluorescent lamps (CCFL) or light-emitting diodes (LEDs) as the backlight
thereof.

[0003] Following the progress of scientific technologies, various types of
touch screens, including optic-type touch screens, have been developed
and largely improved in recent years. The currently available optic-type
touch screens can be divided into out-cell and in-cell touch screens. The
out-cell touch screen mainly uses two infrared light emitting units
arranged at two corners of the screen to emit infrared light, and uses
image acquisition units to acquire shades formed on reflection strips
when the infrared lights are blocked by a touch object. A processor of
the optic-type touch screen computes the shades to find out the position
of the touch point. While the out-cell touch screen can be advantageously
applied to a large-size touch display, the touch display adopting the
out-cell design must have a predetermined mechanism thickness and
therefore fails to be low-profile and light because the touch display
must be provided with reflective strips.

[0004] An in-cell touch screen uses sensors to sense the level of
brightness of a visible light, so as to achieve the purpose of
recognizing the position of a touch point. The in-cell touch screen
advantageous allows integrated manufacturing process, enabling the touch
screen to have reduced thickness. FIG. 1 schematically shows a surface of
a conventional touch display 12. As shown, infrared LEDs 110 in a
backlight source 11 emit invisible lights 111 having a fixed level of
brightness. When an object 13 appears above or on the surface of the
touch display 12, in-cell light sensors of the display 12 would detects
reflected lights 112 of the invisible lights 111 reflected by the object
13, and when there is not any object above or on the surface of the touch
display 12, the in-cell light sensors would output a no-detection
response. In this manner, the touch display technique is implemented.
However, when the image displayed on the display 12 includes different
colors and different levels of brightness, pixels 121 in the display 12
at different positions would show different states, and the reflected
lights 112 reflected by the touch object 13 would have different light
intensities from one another, which results in reduced resolution in a
proximal touch image analysis or easily results in incorrect
determination of the object touch position. For example, when the display
12 has lowered light transmittance due to displaying of specific colors,
even if there is an object 13 approaching toward the display 12, the
in-cell light sensors would detect a relatively low light intensity due
to the low light transmittance and therefore incorrectly determines that
no object is on the display 12.

SUMMARY OF THE INVENTION

[0005] It is therefore a primary object of the present invention to
provide a touch input method and device, so as to solve the problem of
failing to have increased image resolution or having reduced object
recognition power due to different levels of brightness or colors at
different zones of an image displayed on a display screen.

[0006] To achieve the above and other objects, a first embodiment of the
touch input method according to the present invention is applicable to a
touch display, which includes a display module for displaying an image, a
backlight module for emitting a light source, at least one light-sensing
unit for sensing a reflected light of the light source reflected by at
least one object on the display module and generating a light intensity
signal correspondingly, and a processing module for receiving the light
intensity signal and determining at least one touch point on the display
module touched by the at least one object based on the received light
intensity signal. The touch input method includes the steps of using the
processing module to receive the image displayed on the display module,
using the processing module to analyze the image and obtain an image
analysis result; and using the processing module to regulate a light
intensity of an invisible light emitted from the backlight module based
on the image analysis result.

[0007] To achieve the above and other objects, an embodiment of the touch
input device according to the present invention includes a display
module, a backlight module, at least one light-sensing unit, and a
processing module. The display module displays an image. The backlight
module emits a light source. The light-sensing unit senses a reflected
light of the light source reflected by at least one object on the display
module and generates a light intensity signal correspondingly. The
processing module is connected to the display module, the backlight
module and the light-sensing unit, and the processing module receives the
light intensity signal and determines at least one touch point on the
display module touched by the at least one object based on the received
light intensity signal. The processing module also receives the image
displayed on the display module and analyzes the image to obtain an image
analysis result, and regulates a light intensity of an invisible light
emitted from the backlight module based on the image analysis result.

[0008] To achieve the above and other objects, a second embodiment of the
touch input method according to the present invention is applicable to a
touch display, which includes a display module for displaying an image, a
backlight module for emitting a light source, at least one light-sensing
unit for sensing a reflected light of the light source reflected by at
least one object on the display module and generating a light intensity
signal correspondingly, a storage unit for storing a threshold value, and
a processing module for receiving the light intensity signal and the
threshold value and comparing the received light intensity signal with
the threshold value to determine at least one touch point on the display
module touched by the at least one object. The touch input method
includes the steps of using the processing module to receive the image
displayed on the display module; using the processing module to analyze
the image and obtain an image analysis result; and using the processing
module to adjust the threshold value based on the image analysis result.

[0009] To achieve the above and other objects, another embodiment of the
touch input device according to the present invention includes a display
module, a backlight module, at least one light-sensing unit, a storage
unit, and a processing module. The display module displays an image; the
backlight module emits a light source; the light-sensing unit senses a
reflected light of the light source reflected by at least one object on
the display module and generates a light intensity signal
correspondingly. The storage unit stores a threshold value. The
processing module is connected to the display module, the backlight
module, the storage unit and the light-sensing unit and the processing
module receives the light intensity signal and the threshold value, and
compares the received light intensity signal with the threshold value to
determine at least one touch point on the display module touched by the
at least one object.

[0010] The processing module also receives the image displayed on the
display module and analyzes the image to obtain an image analysis result,
and adjusts the threshold value based on the image analysis result.

[0011] With the above arrangements, the touch input method and the device
thereof according to the present invention has one or more of the
following advantages:

[0012] (1) With the touch input method and device of the present
invention, an image displayed on a display screen is analyzed, and an
intensity of an invisible light emitted from the touch display screen is
regulated according to a result from the image analysis, so as to obtain
increased image resolution.

[0013] (2) With the touch input method and device of the present
invention, an image displayed on a display screen is analyzed, and a
sensitivity of the touch display screen in receiving an invisible light
intensity is regulated according to a result from the image analysis, so
as to obtain increased image resolution.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The structure and the technical means adopted by the present
invention to achieve the above and other objects can be best understood
by referring to the following detailed description of the preferred
embodiments and the accompanying drawings, wherein

[0016] FIG. 2 is a block diagram of a first embodiment of a touch input
device according to the present invention;

[0017]FIG. 3 is a schematic cross-sectional view of a display module and
a backlight module for the first embodiment of the touch input device
according to the present invention;

[0018] FIG. 4A is a conceptual view showing an image analysis conducted by
the touch input device of the present invention;

[0019] FIG. 4B is a conceptual view showing another image analysis
conducted by the touch input device of the present invention;

[0020] FIG. 5 is a front view showing a second embodiment of the touch
input device according to the present invention;

[0021]FIG. 6 is a flowchart showing the steps included in a first
embodiment of a touch input method according to the present invention;

[0022]FIG. 7 is a flowchart showing the steps for producing an image
analysis result according to the touch input method of the present
invention;

[0023] FIG. 8 is a block diagram of a third embodiment of the touch input
device according to the present invention;

[0024]FIG. 9A is a conceptual view showing an adjustment of threshold
values conducted by the third embodiment of the touch input device
according to the present invention;

[0025] FIG. 9B is a conceptual view showing another adjustment of
threshold values conducted by the third embodiment of the touch input
device according to the present invention; and

[0026] FIG. 10 is a flowchart showing the steps included in a second
embodiment of the touch input method according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] The present invention will now be described with some preferred
embodiments thereof. For the purpose of easy to understand, elements that
are the same in the preferred embodiments are denoted by the same
reference numerals. Please refer to FIG. 2 that is a block diagram of a
first embodiment of a touch input device 2 according to the present
invention. As shown, the touch input device 2 in the first embodiment
includes a display module 21, a backlight module 22, a light-sensing unit
23, and a processing module 24. The processing module 24 is electrically
connected to the display module 21, the backlight module 22 and the
light-sensing unit 23.

[0028] The display module 21 is able to display an image, and is
preferably a liquid crystal display (LCD) screen or an organic light
emitting diode (OLED) screen. The backlight module 22 includes a visible
light source 221 and an invisible light source 222. The backlight module
22 is arranged behind the display module 21 and can be a direct-lit
backlight module or an edge-lit backlight module. Herein, the invisible
light source 222 is preferably an infrared (IR) light emitted from an IR
light emitting unit or an IR light emitted from a red light emitting unit
having a relatively wider light spectrum. And, the visible light source
221 preferably includes red-light, green-light and blue-light LEDs
emitting red light, green light and blue light, respectively.

[0029] Please also refer to FIG. 3 that is a schematic cross-sectional
view of the display module 21 and the backlight module 22 for the first
embodiment of the touch input device 2 according to the present
invention. In FIG. 3, the display module 21 includes at least one filter
unit 211 and at least one light-sensing unit 23. The filter unit 211 is
able to absorb a visible light while the light-sensing unit 23 is able to
receive an IR light. When an object 26 is in the proximity of a touch
surface of the display module 21, an IR light 2221 emitted from the
invisible light source 222 of the backlight module 22 would be reflected
by the object 26. The light-sensing unit 23 receives the reflected
invisible light 2222 and generates a light intensity signal 231 according
to the reflected IR light 2222. The light intensity signal 231 is sent to
the processing module 24. It is understood the light-sensing unit 23 can
be arranged on the touch input device 2 at different positions without
being limited to that shown in FIG. 3. That is, in addition to being
arranged inside the display module 21, the light-sensing unit 23 can be
otherwise externally attached to the display module 21. And, an areal
sensing can be achieved when a plurality of light-sensing units 23 is
provided.

[0030] In FIG. 2, the processing module 24 includes a touch data analysis
unit 241 and an image analysis unit 242. The touch data analysis unit 241
can analyze according to the received light intensity signal 231 to
obtain touch information, such as the number of touch points, touch
positions, touch gestures, or touch height. The image analysis unit 242
is able to analyze according to the content of the image displayed on the
display module 21 to obtain an image analysis result. The image analysis
result is preferably an image gray level distribution analysis result or
a red light distribution analysis result, so as to obtain the actual
brightness of light or the actual light quantity of IR light transmitted
from different zones of the display module 21.

[0031] In the case IR lights 2221 are emitted from a plurality of red
light emitting units, the image analysis unit 242 is able to conduct the
red light distribution analysis, so as to obtain red light quantities and
IR light quantities at different zones of the display module 21.

[0032] According to the obtained IR light quantities, the processing
module 24 selects to increase or decrease the driving current or driving
voltage of the red light emitting units at different zones. For example,
for zones having relatively weak transmitted IR light quantities, the
driving current or driving voltage of the red light emitting units
thereat can be increased, and for zones having relatively high
transmitted IR light quantities, the driving current or driving voltage
of the red light emitting units thereat can be decreased, so that the IR
lights reflected by the object in different zones of the display module
can have the same reflected light intensity. In this manner, the object
can perform the same touch movement at different zones. While the actual
light quantities of transmitted IR lights at different zones are
different to result in the generation of different light intensity
signals by different sensing units 23, the processing module 24 can still
regulate the IR light intensities to thereby make correct determination
of the touch movement.

[0033] In the case IR lights are emitted from a plurality of IR light
emitting units, the image analysis unit 242 can conduct the gray level
distribution analysis, so as to obtain actual levels of brightness at
different zones of the display module and further obtain the IR light
quantities at different zones accordingly. In this manner, the processing
module 24 can regulate the driving voltage or current used to drive the
IR light emitting units, so that the IR lights reflected by the touch
object at different zones of the display module 21 can have the same
reflected light intensity.

[0034] The driving voltage or driving current of the above-mentioned red
light emitting units or IR light emitting units can be regulated in three
different ways. In the first way, each of the red light emitting units or
the IR light emitting units in the display module 21 is analyzed, so as
to individually regulate the light quantity of the red light emitting
unit or the IR light emitting unit in every pixel 212. In the second way,
the red light emitting units or the IR light emitting units in a
specified zone are analyzed, as shown in FIG. 4A. In FIG. 4A, the
specified zone 213 comprises four (4) pixels 212 in a 2×2 array.
The image analysis unit 242 conducts the red light analysis or the gray
level analysis of the image in each individual specified zone, and finds
an average of the red light quantity or the IR light quantity in the
specified zone, so that the IR light quantity distribution in all
specified zones is obtained and the driving voltage or driving current of
the red light emitting units or the IR light emitting units within the
same specified zone is increased or reduced at the same time. In the
third way, only the red lights or the IR lights emitted from the pixels
212 located surrounding the position of a touch point 214 are analyzed,
as shown in FIG. 4B, and only the driving current or driving voltage of
the analyzed red light emitting units or the analyzed IR light emitting
units is regulated. In the case of having multiple touch points 214, all
the red light emitting units or the IR light emitting units corresponding
to the touch points 214 are analyzed at the same time.

[0035] Please refer to FIG. 5 that is a front view showing a second
embodiment of the touch input device 2 according to the present
invention. The second embodiment is different from the first embodiment
in that, two light-sensing units 23 in the second embodiment are arranged
at an upper left corner and an upper right corner of the display module
21. In this case, the light-sensing units 23 each have an angle of view
wide enough for covering a large part of the display module 21.
Alternatively, an additional light-sensing unit 23 can be provided on the
display module 21 between the first two light-sensing units 23. The
light-sensing units 23 receive the reflected IR lights 2222 to generate
light intensity signals 231 to the touch data analysis unit 241, at where
the above-mentioned touch information can be computed using the known
triangle positioning algorithm. A surface of a display zone of the
display module 21 and a space in front of the display zone are defined as
a coordinate detection zone. Since all other structures of the second
embodiment are similar to the first embodiment, they are not repeatedly
described herein.

[0036]FIG. 6 is a flowchart showing the steps included in a first
embodiment of a touch input method according to the present invention.
The touch input method is applicable to a touch display. The touch
display includes a display module, a backlight module, at least one
light-sensing unit, and a processing module. The display module is able
to display an image, the backlight module is able to emit a light source,
and the light-sensing unit is able to sense a reflected light of the
light source reflected by at least one object on the display module and
generate a light intensity signal corresponding to the reflected light.

[0037] In a first step S10 of the touch input method according to the
first embodiment as shown in FIG. 6, use the processing module to receive
the light intensity signal.

[0038] In a second step S20, use the processing module to analyze
according to the light intensity signal, so as to obtain information
about the touch point.

[0039] In a third step S30, use the processing module to regulate a light
intensity of an invisible light emitted from the backlight module based
on an image analysis result.

[0040] In a fourth step S40, use the processing module to receive the
light intensity signal for a second time and output a touch result
according to the light intensity signal received the second time.

[0041] Please refer to FIG. 7, which is a flowchart showing the steps for
producing the image analysis result used in the third step S30. The steps
include:

[0042] S21: obtain the content of the image displayed on the display
module;

[0043] S22: analyze the image content; and

[0044] S23: produce an image analysis result and then perform the third
step S30 shown in FIG. 6.

[0045] Please refer to FIG. 8 that is a block diagram of a third
embodiment of the touch input device 2 according to the present
invention. The touch input device 2 of the third embodiment is different
from the first embodiment in further having a storage unit 25 for storing
a threshold value 251, and the processing module 24 adjusting the
threshold value according to an image analysis result. When the light
intensity signal 231 is larger than the threshold value 251, the
processing module 24 determines there is a touch object on a position
corresponding to the light intensity signal 231, and the touch input
device 2 would analyze the image content shown by the display module 21
and adjust the threshold value 251 accordingly, as shown in FIGS. 9A and
9B. In FIG. 9A, the image analysis unit 242 conducts an IR analysis of
the displayed image. Since the image content in an upper half of the
frame includes dark colors while the image content in a lower half of the
frame includes light colors, the touch data analysis unit 241 might make
an improper determination when the same threshold value is set for the
upper half and the lower half and the touch object is the same.
Therefore, in the present invention, the threshold value is adjusted
according to the IR analysis by reducing the threshold value
corresponding to the displayed image content with dark colors and
increasing the threshold value corresponding to the display content with
light colors, so that the touch data analysis unit 241 can determine the
correct touch result based on the light intensity signals generated
corresponding to the reflected light intensities and the adjusted
threshold values 251. FIG. 9B is different from FIG. 9A in that the image
analysis unit 242 transforms the displayed image content into different
gray levels, so as to obtain a gray level distribution analysis result,
based on which the processing module 24 regulates the threshold values
251 set for the light-sensing units 23 corresponding to the touch
position. Since all other structures of the third embodiment are similar
to the first embodiment, they are not repeatedly described herein.

[0046] Please refer to FIG. 10 that is a flowchart showing the steps
included in a second embodiment of the touch input method according to
the present invention. The touch input method in the second embodiment is
different from the first embodiment in that the second embodiment is
applicable to a touch display similar to that in the first embodiment but
further including a storage unit for storing a threshold value. In the
touch display for implementing the touch input method in the second
embodiment, the processing module compares the received light intensity
signal with the threshold value to determine the touch result. When the
light intensity signal is larger than the threshold value, the processing
module determines the object on the display module performs a touch
movement; and when the light intensity signal is smaller than the
threshold value, the processing module determines the object does not
perform a touch movement.

[0047] In a first step S50 of the touch input method according to the
second embodiment as shown in FIG. 10, use the processing module to
receive the light intensity signal.

[0048] In a second step S60, use the processing module to analyze
according to the light intensity signal, so as to obtain information
about the touch point.

[0049] In a third step S70, use the processing module to adjust the
threshold value according to an image analysis result.

[0050] In a fourth step S80, the processing module receives the light
intensity signal for a second time and outputs a touch result according
to the light intensity signal received the second time.

[0051] Since the steps for producing the image analysis result according
to the second embodiment of the touch input method are similar to those
included in the flowchart shown in FIG. 7, they are not repeatedly
described herein.

[0052] In the first embodiment of the touch input method, the processing
module regulates the intensity of the invisible light according to the
image analysis result in order to make a correct determination of the
touch movement. On the other hand, in the second embodiment of the touch
input method, the processing module adjusts the threshold value instead
of regulating the invisible light intensity. That is, in the second
embodiment, while the light-sensing units generate different light
intensity signals corresponding to different reflected light intensities,
the processing module can still make a correct determination of the touch
through comparison of the threshold values with the light intensity
signals because the threshold values have already been adjusted by the
processing module according to the image analysis result.

[0053] The present invention has been described with some preferred
embodiments thereof and it is understood that many changes and
modifications in the described embodiments can be carried out without
departing from the scope and the spirit of the invention that is intended
to be limited only by the appended claims.